I was wondering. I just tried uploading a model and everything seemed to work fine, except the smoothing. When I uploaded the .x3d the smoothing groups seemed to have disappeared. Do you have any suggestions on what to do?

3D printers print without any smoothing, what you send in is what gets printed so you'll need to make your models smooth by increasing the number of faces (triangles) whilst trying to stay within the 500k triangle limit. Aiming for triangle sizes less than the minimum detail for a material is a good rule of thumb... this will also help to minimize 'stepping' on smooth curved edges.